<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

    <script>
        function sendAJAX(url) {
            return new Promise((resolve, reject) => {
                const xhr = new XMLHttpRequest();
                xhr.open("GET", url);
                xhr.send();
                xhr.onreadystatechange = () => {
                    if (xhr.status === 4) {
                        if (xhr.status >= 200 && xhr.status < 300) {
                            // 成功
                            resolve(xhr.responseText)
                        } else {
                            // 失败
                            reject(xhr.status)
                        }
                    }
                }
            })
        }
        // sendAJAX("http://www.liulongbin.top:3006/api/getbooks").then(value => {
        //     console.log(value);
        // }).catch(reason => {
        //     console.log(reason);
        // })
        async function main() {
            try {
                // console.log("test");
                let value = await sendAJAX("http://www.liulongbin.top:3006/api/getbooks");
                console.log(value);
            } catch (error) {
                console.error(error);
            }
        }

        main();

    </script>

</body>

</html>